1. Field of the Invention
The present invention relates to managing network information in Access Routers (ARs).
2. Description of the Related Art
Recently, with the rapid popularization of wireless communication and the Internet, the desire of users to use a high quality of Internet service irrespective of time and place has increased rapidly. Furthermore, with improved performance of mobile nodes, such as portable computers or Personal Digital Assistants (PDAs), and advanced wireless communication technologies, the number of users has significantly increased.
Adopting a specific identifier called an Internet Protocol (IP) address in mobile nodes enables users to be successively provided with a service independently used by the users in a link layer, as well as a global roaming problem to be addressed. In this regard, deployment of mobile IPs and a task for standardizing suitable protocols to overcome its shortcoming are under way by the mobileip working group (which is currently divided by mip4 and mip6) in the Internet Engineering Task Force (IETF).
Meanwhile, an explosive increase in the number of Internet users is causing the exhaustion of existing IPv4 Internet addresses. To solve this problem, IPv6 which is a next generation Internet protocol attracts attention. Studies have been performed actively to provide mobility by using IPv6. A mobile IPv6 (hereinafter, referred to as MIPv6) technique of the IETF will be brought into use as a standard technique for a method of supporting user's mobility at a later point in time when the IP protocol for the Internet gets changed to IPv6. The current MIPv6 has been revised to the IETF Internet-Draft version 24 since it was initially proposed in 1996. The MIPv6 status is going to be a Request For Comments (RFC).
In the MIPv6 standard, as a protocol for minimizing a handoff delay and a packet loss when a Mobile Node (MN) moves into a new network, “Fast Handovers for Mobile IPv6” (hereinafter, referred to as FMIPv6, draft-ietf-mobileip-fast-mipv6-07.txt) has been proposed by the IETF mobile ip working group, which is going to be converted into an RFC.
In the FMIPv6, it is assumed that all Access Routers (ARs) have a Candidate Access Router Discovery (CARD) function and that the ARs obtain information of neighboring routers using a function provided by a separate CARD server or terminal.
In the FMIPv6, it is also assumed that the AR has a CARD function. Basic functions of the CARD protocol required herein are as follows.                Reverse address translation: a function of mapping the L2 ID of an AP to an IP address of the AR to which this AP belongs. The MN receives a beacon signal to perform handoff, and this signal includes the L2 ID of the AP. By sending the L2 ID to the current AR, the mobile node requests an IP address of an AR in a new region into which the MN will move. Through such processes, a series of tasks for reducing the handoff delay take place.        Discovery of Current Access Router (CAR) capabilities: in order to perform optimal handoffs, a CAR provides information on allowing an MN to select a suitable CAR by providing information on the CAR to the MN. Information on the IP service, which will be provided, includes services in which the MN may be interested in upon selecting the CAR, for example, seamless handoff support, security functions, wireless performance enhancing functions, administrative and business aspects of providing service to the MN (service provider, cost of access, etc.), availability of certain type of resources with the AR (QoS), etc. The CARD protocol must provide a function of exchanging capability information on the AR.        
The following patents each discloses features in common with the present invention but do not teach or suggest the inventive features specifically recited in the present claims: U.S. Patent Application No. 2003/0227911 to Trossen, entitled CANDIDATE ACCESS ROUTER DISCOVERY, issued on 11 Dec. 2003; U.S. Patent Application No. 2003/0223422 to Igarashi et al., entitled PACKET TRANSMISSION METHOD AND COMMUNICATION SYSTEM, issued on Dec. 4, 2003; U.S. Patent Application No. 2003/0220111 to Kang, entitled DSL MOBILE ACCESS ROUTER SYSTEM AND METHOD, issued on Nov. 27, 2003; U.S. Patent Application No. 2003/0179703 to Levy et al., entitled AUTOMATIC ROUTER CONFIGURATION BASED ON TRAFFIC AND SERVICE LEVEL AGREEMENTS, issued on 25 Sep. 2003; U.S. Patent Application No. 2003/0174667 to Krishnamurthi et al., entitled METHOD AND APPARATUS FOR ALERTING MOBILE NODES OF DESIRABLE ACCESS CHARACTERISTICS, issued on Sep. 18, 2003; U.S. Patent Application No. 2003/0091021 to Trossen et al., entitled PHYSICALLY SCOPED MULTICAST IN MULTI-ACCESS NETWORKS, issued on May 15, 2003; U.S. Patent Application No. 2003/0046413 to Sakakura, entitled NETWORK SYSTEM DYNAMICALLY MADE FOR A SHORT-DISTANCE WIRELESS COMMUNICATION AND NETWORK STRUCTURING METHOD, issued on Mar. 6, 2003; U.S. Patent Application No. 2002/0052964 to Ferner et al., entitled METHOD AND DEVICE FOR DATA COMMUNICATION, issued on May 2, 2002; U.S. Patent Application No. 2004/0114558 to Krishnamurthi et al., entitled END-TO-END LOCATION PRIVACY IN TELECOMMUNICATIONS NETWORKS, issued on Jun. 17, 2004; U.S. Patent Application No. 2004/0092264 to Koodli et al., entitled SYSTEM AND METHOD FOR DISCOVERING NETWORK INTERFACE CAPABILITIES, issued on May 13, 2004; U.S. Patent Application No. 2004/0023653 to O'Neill, entitled CONTROLLING HAND-OFF IN A MOBILE NODE WITH TWO MOBILE IP CLIENTS, issued on Feb. 5, 2004; U.S. Patent Application No. 2004/0004967 to Nakatsugawa et al., entitled MOBILE COMMUNICATION SYSTEM, ROUTER, MOBILE NODE, AND MOBILE COMMUNICATION METHOD, issued on Jan. 8, 2004; U.S. Patent Application No. 2004/0022258 to Tsukada et al., entitled SYSTEM FOR PROVIDING ACCESS CONTROL PLATFORM SERVICE FOR PRIVATE NETWORKS, issued on 5 Feb. 2004; U.S. Patent Application No. 2004/0139224 to Nishimura et al., entitled MOBILE COMMUNICATION SYSTEM, SERVER APPARATUS, AND DATA TRANSMISSION METHOD, issued on Jul. 15, 2004; and U.S. Patent Application No. 2004/0137888 to Ohki, entitled SYSTEM FOR MANAGING MOBILE NODE IN MOBILE NETWORK, issued on Jul. 15, 2004.